*Arnold & Porter (UK) LLP, Tower 42, 25 Old Broad Street, London, EC2N 1HQ, UK E-mail: christopher.stothers@ aporter.com This Hot Topic considers the implications of Merck v. Sigma [1], where the English Court of Appeal referred to the European Court of Justice (ECJ) questions on the application of the specific mechanism. The specific mechanism permits pharmaceutical patents and Supplementary Protection Certificates (SPC) to be enforced against parallel imports from 11 of the new EU Member States if such protection was not available in the new Member State at the relevant time. The ECJ carefully protects the ‘internal market’ required by the Treaty on the Functioning of the EU [2]. Since the 1970s, the ECJ has made it clear that patents cannot be enforced against parallel imports of pharmaceuticals within the EU, on the basis of the Treaty provisions on the free movement of goods (now Articles 34–36). That is the case even where the underlying price differentials that fuel the trade are caused by divergent pricing policies of national healthcare systems or by limitations in patent protection, which mean the product faces generic competition in the exporting country. That is a particular problem where the exporting country refused to grant patent protection for pharmaceutical products in the recent past. This problem has been recognized as the EU has expanded, and patent owners have therefore been given transitional rights to enforce their patents against imports from new Member States. In the case of 11 of the 13 newest joiners from Central and Eastern Europe (Bulgaria, Croatia, the Czech Republic, Estonia, Hungary, Latvia, Lithuania, Poland, Romania, Slovakia and Slovenia), a ‘specific mechanism’ was applied since 1 May 2004 (1 January 2007 for Bulgaria and Romania, and 1 July 2013 for Croatia) [3] that permits the enforcement of patents and SPC against imports if such rights could not be obtained in the exporting Member State when they were filed in the importing Member State. It also requires an importer to notify the patent or SPC owner 1 month before applying to the regulatory authorities for authorization to import such products. This is in addition to any notification of the parallel import authorization by the regulatory authority and to the notification of repackaging, which must be made to the trademark owner before trade begins.